Determine the metaboliism of the organophosphorus insecticide Counter in three Iowa soils, in southern corn rootworms, and in carabid beetles predaceous on rootworms. This is part of an overall study of the fate of Counter in the environment. Counter may replace phorate (Thimet) as a widely used organophosphorus insecticide. Compare organochlorine insecticide residues in reptiles collected from agricultural areas in Iowa where these insecticides have been used for many years with residues in reptiles collected from non-agricultural areas in Arizona and Texas. Evaluate the influence of organochlorine insecticide residues in carabid bettles on natural populations of these beetles.